Method of manufacturing organic EL device, and organic EL device

ABSTRACT

Grooves ( 3 R,  3 G,  3 B) corresponding to red, green and blue respectively are formed on a substrate ( 40 ), and the edge portion of each groove ( 3 R,  3 G,  3 B) is formed so as to be farther from a side of substrate ( 40 ) in order. The edge portion of each groove ( 3 R,  3 G,  3 B) is immersed in an organic EL solution ( 8 R,  8 G,  8 B) of corresponding color, the grooves ( 3 R,  3 G,  3 B) are severally filled with the organic EL solution ( 8 R,  8 G,  8 B) of corresponding color using capillary phenomenon, and thus a full-color organic EL display device is manufactured.

TECHNICAL FIELD

[0001] The present invention relates to a method of manufacturing anorganic EL device and an organic EL device, more particularly to amethod of manufacturing the organic EL device, by which organic ELelements are formed using capillary phenomenon, and an organic ELdevice.

BACKGROUND ART

[0002] An organic EL (Electroluminescence) display device has advantagesthat it is easily manufactured in a thin plate state, has quick responsetime, and consumes less electricity due to no need of back light, whichis prospective as a display device that replaces a liquid crystaldisplay device and a CRT (Cathode Ray Tube).

[0003] Although one piece of film is able to constitute an organic ELlayer (emitting layer) in a monochrome organic EL display device, it isnecessary to form organic EL layers corresponding to the three primarycolors of red (R), green (G) and blue (G) in each pixel in the case of afull-color organic EL display device. In the organic EL display deviceof 170 ppi (pixel per inch), for example, the size of one pixel is 150(m(150 (m and one pixel is constituted by three sub-pixels of which eachsize is 50 (m(150 (m. The three sub-pixels are a red sub-pixel, a greensub-pixel and a blue sub-pixel. Therefore, it is necessary to form eachof a red-emitting organic EL layer, a green-emitting organic EL layer,and a blue-emitting organic EL layer with the width of 50 (m.

[0004] In recent years, a high resolution display device having 200 ppi(pixel size: 127 (m, sub-pixel width: 42.3 (m) to 500 ppi (pixel size:50.8 (m, sub-pixel width: 17 (m) has been required. Further, variouskinds of screen size from as small as approximately 2 inches to as largeas approximately 30 inches have been required.

[0005] The organic EL display device is manufactured by forming TFTs(thin film transistor), insulating films, electrodes, and organic ELlayers on a substrate called a mother glass. Even in the case of theorganic EL display device having a small screen size, a large substratewith the size of approximately 400 m(500 mm to 730 mm(920 mm is used anda plurality of organic EL display devices are simultaneouslymanufactured on one substrate in order to reduce manufacturing cost. Infuture, it is expected that a larger substrate than up to now will beused due to the demand of further reduction of the manufacturing costand a larger screen size.

[0006] In the case of low molecular organic EL material, the organic ELlayers of three colors are formed in each pixel region by depositing theorganic EL material of red emission, green emission and blue emission onthe substrate using a shadow mask. However, in polymeric organic ELmaterial, heat decomposes polymer and thus it is impossible to form theorganic EL film by a deposition method. For this reason, in general, acoater capable of performing an inkjet method is generally used, and inkwhich is made of the organic EL material is sprayed in a dotted stateonto the substrate by each sub-pixel to form the organic EL layer.

[0007] In the coater for the inkjet method, it is necessary to spray aplurality of ink dots in one sub-pixel region. At this point, it isdifficult to form the organic EL layer uniformly in the entire sub-pixelregion because of overlapping of dots or the occurrence of gap betweendots. Consequently, although the coater for the inkjet method can beapplied for a display device having the sub-pixel size of approximately50 (m(150 (m, it may not be applicable for manufacturing a displaydevice of higher resolution.

[0008] Further, as the substrate size increases, it is expected that theposition of dots shift from a predetermined position due to the affectof thermal expansion of substrate.

[0009] Moreover, since the coater for the inkjet method sprays theorganic EL material onto all sub-pixels, it has a drawback that it takesmore time in proportion to the number of sub-pixels and thus themanufacturing cost increases.

DISCLOSURE OF THE INVENTION

[0010] The object of the present invention is to provide a method ofmanufacturing an organic EL device and an organic EL device, whosemanufacturing is easier and the manufacturing cost is reduced comparingto a conventional method, and which is applicable for a high-resolutiondisplay device.

[0011] In the present invention, grooves are formed in the insulatingfilm on the substrate and the grooves are filled with a solution inwhich the organic EL material is dissolved using capillary phenomenon.

[0012] For example, in forming the organic EL layer, the solution inwhich the organic EL material is dissolved is prepared. Then, after thegrooves are filled with the solution using capillary phenomenon, thesolution is dried to form the organic EL layer in the grooves. Thus, theorganic EL layer having a uniform thickness is easily formed. Toincrease luminous efficiency of organic EL element, there are caseswhere a buffer layer (such as a hole transport layer and an electrontransport layer) is formed between the electrode and the organic ELlayer. By selecting a solution in which the material of the bufferlayers are dissolved, the buffer layers can be formed using capillaryphenomenon as well similar to the organic EL layer.

[0013] Further, in the case of using organic electrodes, electrodelayers can be formed using capillary phenomenon similar to the organicEL layer by selecting a solution in which the electrode material isdissolved.

[0014] When forming a full-color organic EL display device, it isrequired to individually form the red-emitting organic EL layer, thegreen-emitting organic EL layer, and the blue-emitting organic EL layer.In the present invention, three sets of grooves are formed per one pixeland any one of the red-emitting organic EL layer, the green-emittingorganic EL layer, and the blue-emitting organic EL layer is formed ineach set of grooves by using capillary phenomenon. This makes itpossible to easily form the organic EL layer having each luminescencecolor in a uniform thickness, and thus to manufacture the full-colororganic EL display device of superior display quality at a low cost.

[0015] If the luminous efficiency of the red-emitting organic EL layer,the green-emitting organic EL layer, and the blue-emitting organic ELlayer is not the same, adjusting the number or the width of grooves ineach set makes apparent luminescence intensity be the same.

[0016] Further, individually controlling the luminescence of the organicEL layer of a same set (same luminescence color) in one pixelfacilitates gradation display (middle gradation display).

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 is a circuit diagram showing an example of the organic ELdevice of the present invention.

[0018]FIG. 2 is a schematic cross-sectional view showing a structureexample of the organic EL device of the present invention.

[0019]FIG. 3 is a schematic view showing the principle of the presentinvention.

[0020]FIG. 4 is a schematic view showing the method of manufacturing theorganic EL device of the first embodiment of the present invention (1).

[0021]FIG. 5 is a schematic view showing the method of manufacturing theorganic EL device of the first embodiment of the present invention (2).

[0022]FIG. 6 is a schematic view showing the method of manufacturing theorganic EL device of the first embodiment of the present invention (3).

[0023]FIG. 7 is a schematic view showing the method of manufacturing theorganic EL device of the first embodiment of the present invention (4).

[0024]FIG. 8 is a schematic view showing the method of manufacturing theorganic EL device of the first embodiment of the present invention (5).

[0025]FIG. 9 is a schematic view showing the method of manufacturing theorganic EL device of the first embodiment of the present invention (6).

[0026]FIG. 10 is a schematic view showing the method of manufacturingthe organic EL device of the first embodiment of the present invention(7).

[0027]FIG. 11 is a schematic view showing the method of manufacturingthe organic EL device of the first embodiment of the present invention(8).

[0028]FIG. 12 is a schematic view showing the method of manufacturingthe organic EL device of the first embodiment of the present invention(9).

[0029]FIG. 13 is a schematic view showing the method of manufacturingthe organic EL device of the first embodiment of the present invention(10).

[0030]FIG. 14 is a schematic view showing the method of manufacturingthe organic EL device of the first embodiment of the present invention(11).

[0031]FIG. 15 is a schematic view showing the method of manufacturingthe organic EL device of the first embodiment of the present invention(12).

[0032]FIG. 16 is a schematic view showing the method of manufacturingthe organic EL device of the first embodiment of the present invention(13).

[0033]FIG. 17 is a schematic view showing the method of manufacturingthe organic EL device of the first embodiment of the present invention(14).

[0034]FIG. 18 is a schematic view showing a substrate in which a largenumber of grooves are formed for each luminescence color.

[0035]FIG. 19 is a schematic view showing the state where the substrateis made perpendicular and immersed in a solution.

[0036]FIG. 20 is a schematic view showing the state where the substrateis tilted and immersed in the solution.

[0037]FIG. 21 is a schematic cross-sectional view showing a structureexample of the organic EL device where a buffer layer is providedbetween an electrode and an organic EL layer.

[0038]FIG. 22 is a schematic view showing the method of manufacturingthe organic EL display device of the second embodiment in the presentinvention.

[0039]FIG. 23 is a schematic view showing an example where the number ofgrooves for blue sub-pixel is larger than the number of grooves for redand green sub-pixels.

[0040]FIG. 24 is a schematic view showing an example where the width ofgrooves for blue sub-pixel is wider than the width of grooves for redand green sub-pixels.

[0041]FIG. 25 is a view showing the method of manufacturing the organicEL device of the third embodiment of the present invention (1).

[0042]FIG. 26 is a view showing the method of manufacturing the organicEL device of the third embodiment of the present invention (2).

[0043]FIG. 27 is a view showing the method of manufacturing the organicEL device of the third embodiment of the present invention (3).

[0044]FIG. 28 is a view showing the method of manufacturing the organicEL device of the third embodiment of the present invention (4).

[0045]FIG. 29 is a view showing the method of manufacturing the organicEL device of the third embodiment of the present invention (5).

[0046]FIG. 30 is a view showing the method of manufacturing the organicEL device of the third embodiment of the present invention (6).

[0047]FIG. 31 is a view showing the method of manufacturing the organicEL device of the third embodiment of the present invention (7).

[0048]FIG. 32 is a view showing the method of manufacturing the organicEL device of the third embodiment of the present invention (8).

[0049]FIG. 33 is a view showing the method of manufacturing the organicEL device of the third embodiment of the present invention (9).

[0050]FIG. 34 is a view showing the method of manufacturing the organicEL device of the third embodiment of the present invention (10).

[0051]FIG. 35 is a view showing the method of manufacturing the organicEL device of the third embodiment of the present invention (11).

[0052]FIG. 36 is a view showing the method of manufacturing the organicEL device of the third embodiment of the present invention (12).

BEST MODE FOR CARRYING OUT THE INVENTION

[0053] The embodiments of the present invention will be described basedon the drawings as follows.

[0054]FIG. 1 is the circuit diagram showing an example of the organic ELdisplay device of active matrix type.

[0055] A plurality of data lines 41 and power supply lines 42, whichextend in vertical directions, and a plurality of scanning lines 43extending in horizontal directions are formed on a glass substrate 40.Regions surrounded by the data lines 41, the power supply lines 42 andthe scanning lines 43 are sub-pixel regions. In this embodiment, thesub-pixels of red emission, green emission and blue emission arearranged in due order in the horizontal directions, and the sub-pixelsof a same color are arranged in the vertical directions.

[0056] A TFT for switching 44, a TFT for driving 45, a capacitor 46 andan organic EL element (light-emitting element) 47 are provided for eachsub-pixel region.

[0057] The gate, the source and the drain of the TFT for switching 44are respectively connected to the scanning line 43, the gate of the TFTfor driving 45, and the data line 41. Further, the TFT for driving 45 isconnected between the power supply line 42 and the anode of the organicEL element 47. Furthermore, the capacitor 46 is connected between thegate of the TFT for driving 45 and the power supply line 42.

[0058] In the organic EL display device of this configuration, when apredetermined voltage is supplied to each data line 41 and a scanningsignal is supplied only to the scanning line 43 of the first row, theTFTs for switching 44 connected to the scanning line 43 on the first roware turned on to accumulate the voltage of data line 41 in the capacitor46.

[0059] A current corresponding to the voltage flows from the powersupply line 42 to the organic EL element 47 via the TFT for driving 45,and each organic EL element 47 on the first row emits light.Subsequently, when the predetermine voltage is supplied to each dataline 41 and the scanning signal is supplied only to the scanning line 43on the second row, each organic EL element 47 on the second row emitslight.

[0060] As described, by sequentially driving the organic EL elements oneach row, a desired character or image can be displayed.

[0061]FIG. 2 is the schematic cross-sectional view showing the structureof the above-described organic EL display device of active matrix type.Note that the TFT for switching shown in FIG. 1 is not shown in FIG. 2.

[0062] An underlying insulating film 51 made of SiO₂ or anotherinsulating material is formed on the glass substrate 40, and apolysilicon film 52 that is an operating layer of TFT is selectivelyformed on the underlying insulating film 51. A pair of highlyconcentrated impurity regions 52 a, which are the source/drain of TFT,are formed in the polysilicon film 52, sandwiching a channel region.

[0063] A gate insulating film 53 made of SiO₂ or another insulatingmaterial is formed on the polysilicon film 52 and underlying insulatingfilm 51. Further, the gate electrode 54 of TFT is formed on the gateinsulating film 53 in the area above the channel region of thepolysilicon film 52. Then, an interlayer insulating film 55 made of SiO₂or another insulating material is formed on the gate electrode 54 andgate insulating film 53.

[0064] Wiring 56 is formed on the interlayer insulating film 55 in apredetermined pattern. The predetermined wiring of the wiring 56 iselectrically connected to the highly concentrated impurity regions 52 aof TFT for driving via contact holes.

[0065] The wiring 56 is covered with an interlayer insulating film 57made of SiO₂ or another insulating material. An anode 58 made of ITO(Indium-Tin Oxide) is formed on the interlayer insulating film 57 in apredetermined pattern. The anode 58 is electrically connected to one ofthe highly concentrated impurity regions 52 a (source) of TFT fordriving via the contact hole and wiring 56.

[0066] An insulating film 60 made of SiO₂ or another insulating materialand an insulating film 61 made of polyimide are laminated on the anode58 and interlayer insulating film 57. A groove 62 extending in thevertical directions of the document of FIG. 2 is formed in theinsulating films (60, 61).

[0067] An organic EL layer (emitting layer) 59 is formed on the anode 58at the bottom of the groove 62. Although the anode 58 is individuallyformed by each sub-pixel region, the organic EL layer 59 is formedacross a plurality of sub-pixels arranged in the longitudinal directionof the groove 62.

[0068] A cathode 63 made of an Al/Li (aluminum/lithium) alloy, forexample, is formed on the insulating film 61 and the organic EL layer 59inside the groove 62. The anode 58, the organic EL layer 59 and thecathode 63 constitute the organic EL element 47 shown in FIG. 1.

[0069] Note that one or more of the electron transport layer, the holetransport layer and a contact layer (layer for improving the contactproperty) may be arranged between the anode 58 and cathode 63 in orderto improve a luminous efficiency of the organic EL layer 59.Hereinafter, the electron transport layer, hole transport layer andcontact layer are referred to as a buffer layer.

[0070] In the organic EL display device of this configuration, when avoltage is supplied between the anode 58 and cathode 63, the organic ELlayer 59 emits light in a color (red, green or blue) corresponding toits material, and the light emits toward the substrate 40.

[0071] In the following, the principle of the method of manufacturingthe organic EL device in the present invention will be described. In thepresent invention, the edge of the groove formed on the substrate isimmersed in the solution in which the organic EL material is dissolved,and the groove is filled with the solution by capillary phenomenon toform the organic EL layer.

[0072] When the substrate, on which the grooves are formed, is made tostand while its edge is immersed in liquid having property to wet thesubstrate material, capillary phenomenon allows the liquid to go up inthe grooves. The inventors of this application has once conductedresearch on manufacturing polyacetylene narrow wire by using an SiO₂substrate on which grooves were formed and Ziegler-Natta catalyst. Atthat time, the inventors confirmed that a toluene solution went up thegrooves by way of experiment, and presented the result in the followingthesis.

[0073] Nobuo Sasaki, Yoshihiro Takao, and Nagisa Ohsako, ‘SelectiveGrowth of Polyacetylene Narrow Wires Utilizing Capillary phenomenon ofCatalyst Solution in Grooves’, Japanese Journal of Applied Physics,Vol.31, pp.L741-L743(1992).

[0074] As shown in FIG. 3, when a groove 12 is formed on a substrate 11and the edge of groove 12 is immersed in liquid 13 having property towet the substrate 11, capillary phenomenon allows the liquid 13 to go upin the groove 12. When, in FIG. 3, the substrate 11 is allowed to standupright to a liquid surface, the relationship shown in the followingequation (1) holds supposing that the ingression distance (height ofliquid going up) of liquid 13 into the groove 12 is h, the density ofliquid 13 is (, the surface tension of liquid 13 is (, gravitationalacceleration is g, the width of groove 12 is w, the depth of groove 12is d, and contact angle of liquid 13 to the substrate 11 is (.

h(gw=((2d+w)cos(   (1)

[0075] For example, when the width w and the depth d of groove 12 are0.5 (m and 0.5 (m, respectively, the ingression distance (height) h ofliquid 13 is 17 m. Further, when the width w and the depth d of groove12 are 3 (m and 1 (m, respectively, the ingression distance (height) hof liquid 13 is 4.8 m.

[0076] Note that these are calculated values when the substrate 11 isSiO₂, the liquid 13 is toluene, the density ( of liquid 13 is 0.8669g/cm³, the surface tension ( of liquid 13 is 28.52 dyn/cm and thecontact angle ( of liquid 13 to the substrate 11 is 30 degrees.

[0077] It is to be noted that the following equation (2) holds when thesubstrate 11 is immersed in the liquid 13 tilting by angle ( from anupright state.

h(gw cos(=((2d+w)cos(   (2)

[0078] As it is clear from equation (2), the ingression distance h ofliquid 13 can be larger by tilting the substrate 11.

[0079] Next, the specific embodiments of the method of manufacturing theorganic EL device and the organic EL device in the present inventionwill be described.

FIRST EMBODIMENT

[0080] The full-color organic EL display device uses a red-emittingorganic EL material, a green-emitting organic EL material, and ablue-emitting organic EL material. For example, the red-emitting organicEL material iscopoly(2,5-didodecyloxy-1,4-phenylenebutadiynylene)(3-dodecyloxycarbonylthienylenebutadiynylene). Further, the green-emitting organicEL material iscopoly(2,5-dialkoxy-p-phenylenebutadiynylene)(2-alkoxy-m-phenylenebutadiynylene).The blue-emitting organic EL material iscopoly((4,4′-biphenylylenelbutadiynylene)(4-dodecyloxy-m-phenylenebutadiynylene).

[0081] The embodiments of the present invention uses solutions whereeach of these organic EL materials is dissolved in toluene, and aband-shaped organic EL layer is formed using capillary phenomenon. Theconcentration of the organic EL material in the solution is 2% byweight, for example.

[0082] In the following, the method of manufacturing the organic ELdevice (display device) of the first embodiment will be described withreference to the cross-sectional view shown in FIG. 2 and the schematicdrawings shown in FIGS. 4 to 17. It is assumed that the TFTs, wiring 56,interlayer insulating film 55, 57, anode 58 and the like are formed onthe substrate 40 by a known deposition method and a knownphotolithography method (refer to FIG. 2).

[0083] After the anode 58 is formed on the interlayer insulating film 57by ITO, SiO₂ is deposited on the entire upper surface of the substrate40 to form the insulating film 60, and the insulating film 60 covers theanode 58. Subsequently, a groove for red sub-pixel 3R, a groove forgreen sub-pixel 3G and a groove for blue sub-pixel 3B are formed on theinsulating film 60 as shown in FIG. 4.

[0084] The three grooves (3R, 3G, 3B) are formed such that the distanceof the edge of the groove for blue sub-pixel 3B is farthest from oneside of the substrate 40 (the bottom side in FIG. 4), followed by theedge of the groove for green sub-pixel 3G and the edge of the groove forred sub-pixel 3R, which are closer to the side in this order. AlthoughFIG. 4 shows only one each of the grooves (3R, 3G, 3B) for simplifyingexplanation, a large number of grooves (3R, 3G, 3B) are actually formedon the substrate 40 as shown in FIG. 18.

[0085] Then, as shown in FIG. 5, stoppers (5 a, 5 b) are formed in themiddle of the groove for red sub-pixel 3R and groove for green sub-pixel3G to prevent the organic EL material from entering the grooves (3R,3G). The stopper 5 a is arranged at a farther position from one side ofthe substrate 40 than the stopper 5 b. The stoppers (5 a, 5 b) are madeof photoresist and formed via selective exposure and developmentprocess. The both stoppers (5 a, 5 b) are formed on the substrate 40outside a display region (region where sub-pixels are arranged).

[0086] Next, as shown in FIG. 6, there is prepared a container with apolymeric organic EL solution (hereinafter, referred to as a bluesolution) 8B that becomes a blue emitting layer. Then, the edge ofgroove 3B is immersed in the blue solution 8B while standing thesubstrate 40 upright. Consequently, capillary phenomenon allows the bluesolution 8B to enter the groove 3B above the liquid surface and theentire groove 3B is filled with the blue solution 8B.

[0087] At this time, the blue solution 8B enters the grooves (3R, 3B) aswell, but the stoppers (5 a, 5 b) block the ingression of blue solution8B above the stoppers (5 a, 5 b).

[0088] Next, the substrate 40 is pulled out from the blue solution 8B,and dried to let toluene evaporate from the blue solution 8B in thegrooves. As a result, a blue-emitting organic EL layer 6B is formed inthe groove 3B as shown in FIG. 7.

[0089] Subsequently, as shown in FIG. 8, a container with resiststripper 4 is prepared, and the substrate 40 is immersed in the resiststripper 4 to a position where the stopper 5 b of the groove for greensub-pixel 3G immerses. Then, the substrate 40 is pulled out after thestopper 5 b is stripped off. Thus, the organic EL layer 6B under theliquid surface of the stripper 4 is removed as shown in FIG. 9.

[0090] Next, as shown in FIG. 10, there is prepared a container with apolymeric organic EL solution (hereinafter, referred to as a greensolution) 8G that becomes a green emitting layer. Then, the edge ofgroove 3G is immersed in the green solution 8G while standing thesubstrate 40 upright. Consequently, capillary phenomenon allows thegreen solution 8G to enter the groove 3G above the liquid surface andthe entire groove 3G is filled with the green solution 8G.

[0091] At this time, the green solution 8G does not enter the groove 3Bsince the edge of the groove for blue sub-pixel 3B is apart from theliquid surface of green solution 8G. Further, since the stopper 5 a isprovided for the groove for red sub-pixel 3R, the green solution 8Genters the groove 3R only to the position of stopper 5 a.

[0092] Next, the substrate 40 is pulled out from the green solution 8G,and dried to let toluene evaporate from the green solution 8G in thegrooves. As a result, a green-emitting organic EL layer 6G is formed inthe groove 3G as shown in FIG. 11.

[0093] Subsequently, as shown in FIG. 12, the substrate 40 is immersedupright in the resist stripper 4 to the position where the stopper 5 aof the groove for red sub-pixel 3R immerses and the stopper 5 a isremoved. Thus, the green emitting layer 6G under the liquid surface isremoved as shown in FIG. 13.

[0094] Next, as shown in FIG. 14, there is prepared a container with apolymeric organic EL solution (hereinafter, referred to as a redsolution) 8R that becomes a red emitting layer. Then, the edge of groove3R is immersed in the red solution 8R while standing the substrate 40upright. Consequently, capillary phenomenon allows the red solution 8Rto enter the groove 3R above the liquid surface and the entire groove 3Ris filled with the red solution 8R.

[0095] At this time, the red solution 8R does not enter the grooves (3B,3G) since the edge of the groove for blue sub-pixel 3B and groove forgreen sub-pixel 3G is apart from the liquid surface of red solution 8R.

[0096] Next, the substrate 40 is pulled out from the red solution 8R inthe container, and dried to let toluene evaporate from the red solution8R in the grooves. As a result, a red emitting layer 6R is formed in thegroove 3R as shown in FIG. 15.

[0097] Thus, the edge of groove 3R is immersed in the resist stripper 4to remove the red emitting layer 6R at the edge portion as shown in FIG.16.

[0098] As described above, the red emitting layer 6R, green emittinglayer 6G and blue emitting layer 6B are respectively formed in thegrooves (3R, 3G, 3B) as shown in FIG. 17.

[0099] After that, polyimide is coated on the entire surface to form theinsulating film 62, and grooves on which the organic EL layer 59 (6R,6G, 6B) is exposed are formed in the insulating film 62 (refer to FIG.2). Then, the Al/Li alloy is deposited on the entire surface by asputtering method, for example, to form the cathode 63. The organic ELdisplay device is manufactured in this manner.

[0100] According to this embodiment, the solution, in which the organicEL material is dissolved, is allowed to enter the grooves usingcapillary phenomenon to form the organic EL layer, so that the formationof organic EL layer is quite easy and thus the manufacturing cost isreduced, whereas the organic EL layer of a uniform thickness can beformed. Furthermore, it can be applied for the high-resolution organicEL display device by adjusting the width of the grooves (3R, 3G, 3B).

[0101] Although description has been made in the above-describedembodiment for the example where the polymeric organic EL material wasused as the material of organic EL layer, the present invention is notlimited to the polymeric organic EL material and it is possible to usethe low molecular organic EL material as long as it is soluble insolvent.

[0102] In addition, in the above-described embodiment, the edge portionsof grooves (3R, 3G, 3B) were immersed in the solution 8 while standingthe substrate 40 upright to the liquid surface of the organic ELsolution 8 (8R, 8G, 8B) as shown in FIG. 19. However, the substrate 40may be immersed in the solution 8 with a slope as shown in FIG. 20. Inthis case, the distance of the solution 8 going up in the grooves bycapillary phenomenon is larger comparing to the case where the substrate40 is immersed upright in the solution 8.

[0103] Moreover, as described above, it is often the case where thebuffer layer such as the hole transport layer, electron transport layerand contact layer is arranged.

[0104]FIG. 21 is the view showing the organic EL display device where abuffer layer (hole transport layer) 64 made up of PEDT/PSS is providedbetween the anode 58 and organic EL layer 59. This layer is formed bydissolving PEDT/PSS in isopropyl alcohol and filling the grooves with itusing capillary phenomenon in the same manner as the above-describedforming method of organic EL layer.

[0105] Further, since the flow of current between organic EL layers canbe disregarded when the buffer layer is in high resistance, the bufferlayer is not formed for each organic EL element but may be commonlyformed for each organic EL element. In such a case, the anode 58 isformed on the interlayer insulating film 57, the buffer layer 64 andinsulating film 60 are further formed on the entire surface of thesubstrate 40, and then, the grooves are formed in the insulating film 60to form the organic EL layer using capillary phenomenon as describedabove.

[0106] Although the anode 58 is formed by ITO in the example shown inFIG. 21, it may be formed by conductive polymeric material instead ofITO. In this case, it is also possible to form the layer by filling thegrooves with a conductive polymeric material solution using capillaryphenomenon similar to the above-described forming method of the organicEL layer. Highly conductive material is required as an electrodematerial, and the electric conductivity of 30 to 200 S/cm is easilyobtained when polyaniline is used for example. An N-methyl1-2-pyrrolidone solution having 0.5% by weight is used in order to fillthe grooves with polyaniline by capillary phenomenon.

[0107] Furthermore, although the groove 62 was linearly formed in theabove-described first embodiment, the groove 62 may be formed in a bentor curved shape.

SECOND EMBODIMENT

[0108]FIG. 22 is the schematic view showing the method of manufacturingthe organic EL display device of the second embodiment in the presentinvention. Description will be made with reference to thecross-sectional view of FIG. 2 in this embodiment as well.

[0109] In this embodiment, after the anode 58 and the interlayerinsulating film 60 are formed similar to the first embodiment, aplurality of grooves (4 for each color in FIG. 22) are formed for oneanode 58. Note that the three grooves (3R, 3G, 3B) are formed such thatthe edge of the grooves for red sub-pixel 3R is closest to one side ofthe substrate 40 (the bottom side in FIG. 22), followed by the groovesfor green sub-pixel 3G and the grooves for blue sub-pixel 3B, whichbecome farther from the side of substrate 40 in this order.

[0110] Then, the grooves for red sub-pixel 3R is filled with the redsolution, the grooves for green sub-pixel 3G is filled with the greensolution, the grooves for blue sub-pixel 3B is filled with the bluesolution similar to the first embodiment, and thus forming thered-emitting organic EL layer 6R, green-emitting organic EL layer 6G andblue-emitting organic EL layer 6B.

[0111] Subsequently, the insulating film 61 is formed, the groove isformed in the insulating film 61 to expose the organic EL layers (6R,6G, 6B), and then the cathode 63 made up of the Al/Li alloy is formed,similar to the first embodiment.

[0112] In addition to the same effects obtained in the first embodiment,this embodiment exerts the effects shown below.

[0113] When the luminous efficiency of organic EL layer is differentamong luminescence colors, the luminescence intensity of the redsub-pixel, green sub-pixel and blue sub-pixel is made to be uniform byadjusting the number of grooves for each color. Generally, the luminousefficiency of the blue organic EL layer is lower than that of the redorganic EL layer and green organic EL layer, so that the number of thegrooves for red sub-pixel 3R and the grooves for green sub-pixel 3G areset to three each for one sub-pixel, the number of the grooves for bluesub-pixel 3B is set to five for one sub-pixel, and thus the luminescenceintensity of each sub-pixel can be uniformized.

[0114] Note that the width of the grooves for blue sub-pixel may bethicker than that of the grooves for red sub-pixel 3R and the groovesfor green sub-pixel 3G. Accordingly, it is also possible to uniformizethe luminescence intensity of each sub-pixel.

MODIFIED EXAMPLE

[0115] When a plurality of organic EL layers are formed in one sub-pixelregion, as shown in FIG. 22, a plurality of TFTs for driving may beformed for one sub-pixel to allow each organic EL layer to emit lightindividually. Allowing a plurality of organic EL layers in one sub-pixelto individually emit light facilitates the display of middle gradation.

[0116] In other words, the organic EL display device of active matrixtype usually displays middle gradation by controlling the electriccurrent flowing in the TFTs for driving. However, in the case ofcontrolling the current flowing in the TFTs for driving to displaymiddle gradation, the variation of TFT characteristics could causedisplay unevenness. As described above, when a plurality of TFTs fordriving are formed per one sub-pixel and gradation is displayed byindividually controlling the luminescence of each organic EL layer, theoccurrence of display unevenness caused by the variation of TFTcharacteristics is prevented. Note that a plurality of grooves in onesub-pixel may be formed in different width from each other.

[0117] Furthermore, as described above, by forming a plurality of TFTsfor driving per one sub-pixel to individually control the luminescenceof each organic EL layer, redundancy can be bestowed and the reductionof production yield due to the disconnection of wire or the like can beprevented.

THIRD EMBODIMENT

[0118] FIGS. 25 to 36 are the views showing the method of manufacturingthe organic EL display device of the third embodiment in the presentinvention. Description will be made with reference to thecross-sectional view of FIG. 2 in this embodiment as well.

[0119] In this embodiment, after the anode 58 and interlayer insulatingfilm 60 are formed on the substrate 40 similar to the first embodiment,the groove for red sub-pixel 3R, groove for green sub-pixel 3G andgroove for blue sub-pixel 3B are formed as shown in FIG. 25. Althoughonly one each of the grooves (3R, 3G, 3B) is shown in FIG. 25 tosimplify explanation, a large number of the grooves (3R, 3G, 3B) areactually formed on the substrate 40.

[0120] At this time, the edge of the three grooves (3R, 3G, 3B) arearranged such that the distance of the edge of the grooves for bluesub-pixel 3B is farthest from one side of the substrate 40 (the bottomside in FIG. 25), followed by the groove for green sub-pixel 3G and thegroove for red sub-pixel 3R, which are closer to the side in this order.Additionally, the groove 3B is arranged such that the other end thereofis closer to the other side of the substrate 40 (the top side in FIG.25) than the other sides of the grooves (3R, 3G).

[0121] Subsequently, as shown in FIG. 26, the stopper 5 a is formed byphotoresist to prevent the organic EL solution from entering the groovefor red sub-pixel 3R.

[0122] Next, as shown in FIG. 27, there is prepared a container with thepolymeric organic EL solution (blue solution) 3G that becomes the greenemitting layer. Then, the edge of groove 3G is immersed in the greensolution 8G while standing the substrate 40 upright. Consequently,capillary phenomenon allows the green solution 8G to enter the groove 3Gabove the liquid surface and the entire groove 3G is filled with thegreen solution 8G.

[0123] At this time, since the edge of groove 3B is apart from the greensolution, the green solution 8G does not enter the groove 3B. Further,the green solution 8G enters the groove 3R to the position of stopper 5a. Next, the substrate 40 is pulled out from the green solution 8G, anddried to let toluene evaporate from the green solution 8G in thegrooves. As a result, a green-emitting organic EL layer 6G is formed inthe groove 3G as shown in FIG. 28.

[0124] Subsequently, as shown in FIG. 29, a container with the resiststripper 4 is prepared, and the substrate 40 is immersed in the resiststripper 4 to a position where the stopper 5 a of the groove for redsub-pixel 3R immerses. Then, the substrate 40 is pulled out after thestopper 5 a is stripped off. Thus, the organic EL layer 6G under theliquid surface of the stripper 4 is removed as shown in FIG. 30.

[0125] Next, as shown in FIG. 31, a container with the polymeric organicEL solution (red solution) 8R that becomes the red emitting layer isprepared. Then, the edge of groove 3R is immersed in the red solution 8Rwhile standing the substrate 40 upright. Consequently, capillaryphenomenon allows the red solution 8R to enter the groove 3R above theliquid surface and the entire groove 3R is filled with the red solution8R.

[0126] At this time, since the edge of the groove for blue sub-pixel 3Band the edge of the groove for green sub-pixel 3G are apart from the redsolution 8R, the red solution 8R does not enter the grooves (3B, 3G).

[0127] Next, the substrate 40 is pulled out from the container, anddried to let toluene evaporate from the red solution 8R in the groove.As a result, a red-emitting organic EL layer 6R is formed in the groove3R as shown in FIG. 32.

[0128] Subsequently, the edge of groove 3R is immersed in the resiststripper 4 to remove the red emitting layer 6R in the edge portion asshown in FIG. 33. FIG. 34 shows the state where the edge portion of redemitting layer 6R in the groove 3R has been removed.

[0129] Next, as shown in FIG. 35, a container with the polymeric organicEL solution (blue solution) 8B that becomes the blue emitting layer isprepared. Then, the edge of the other end of groove 3B is immersed inthe blue solution 8B while standing the substrate 40 upright.Consequently, capillary phenomenon allows the blue solution 8B to enterthe groove 3B above the liquid surface and the entire groove 3B isfilled with the blue solution 8B.

[0130] At this time, since the edge of the other sides of the groove forred sub-pixel 3R and the edge of the groove for green sub-pixel 3G areapart from the blue solution 8B, the blue solution 8B does not enter thegrooves (3R, 3G). Next, the substrate 40 is pulled out from the bluesolution, and dried to let toluene evaporate from the blue solution 8Bin the groove. As a result, a green-emitting organic EL layer 6B isformed in the groove 3B as shown in FIG. 36.

[0131] Subsequently, similar to the first embodiment, the insulatingfilm 61 is formed and then the grooves are formed in the insulating film61 to expose the organic EL layers (6R, 6G, 6B). After that, the cathode63 is formed by the Al/Li alloy.

[0132] The effects same as those of the first embodiment are alsoobtained in this embodiment. Further, this embodiment has an advantagethat the stopper 5 a may be formed only in the groove for red sub-pixel3R and only one stripping process to the stopper is required.

1. A method of manufacturing an organic EL device, comprising the steps of: forming grooves in an insulating film on a substrate; filling said grooves with a solution in which an organic EL element material is dissolved; and drying said solution.
 2. A method of manufacturing an organic EL device, comprising the steps of: forming first and second grooves in an insulating film on a substrate while the positions of their one edge portions are shifted from each other; forming a stopper to prevent a solution from entering said first groove; immersing said one edge portions of said first and second grooves in a first solution in which a first organic EL material is dissolved, and filling said second groove with said first solution while said stopper prevents said first solution from entering said first groove; removing said stopper; and immersing said one edge portion of said first groove in a second solution in the state where said second groove is apart from said second solution in which a second organic EL material is dissolved, and filling said first groove with said second solution.
 3. A method of manufacturing an organic EL device, comprising the steps of: forming first and second grooves in an insulating film on a substrate while the positions of their one edge portions and the other edge portions are shifted from each other; immersing said one edge portion of said second groove in a first solution in the state where said first groove is apart from said first solution in which a first organic EL material is dissolved, and filling said second groove with said first solution; and immersing said other edge portion of said first groove in a second solution in the state where said second groove is apart from said second solution in which a second organic EL material is dissolved, and filling said first groove with said second solution.
 4. A method of manufacturing an organic EL device, comprising the steps of: forming first, second and third grooves in an insulating film on a substrate while the positions of their one edge portions are shifted from each other; forming first and second stoppers to prevent a solution from entering said first and second grooves; preparing a first solution in which an organic material of a first luminescence color is dissolved; immersing said other edge portions of said first, second and third grooves in said first solution, and filling said third groove with said first solution while said first and second stoppers prevent said first solution from entering said first and second grooves; removing said second stopper; preparing a second solution in which an organic material of a second luminescence color is dissolved; immersing said one edge portions of said first and second grooves in said second solution in the state where said third groove is apart from said second solution, and filling said second solution in said second groove while said first stopper prevents said second solution from entering said second groove; preparing a third solution in which an organic EL material of a third luminescence color is dissolved; and immersing said one edge portion of said first groove in said third solution in the state where said second and third grooves are apart from said third solution, and filling said third groove with said third solution.
 5. The method of manufacturing the organic EL device according to claim 4, wherein a plurality of said first, second and third grooves are formed for one pixel.
 6. The method of manufacturing the organic EL device according to claim 5, wherein at least one of said first, second and third grooves is formed in the different number from the number of the other grooves.
 7. The method of manufacturing the organic EL device according to claim 4, wherein at least one of said first, second and third grooves is formed in a different width from the other grooves.
 8. A method of manufacturing an organic EL device, comprising the steps of: forming first, second and third grooves in an insulating film on a substrate while the positions of their one edge portions are shifted from each other and the position of the other edge portion of the third groove is shifted from the edge portions of said first and second grooves; forming a stopper to prevent a solution from entering said first groove; preparing a first solution in which an organic material of a first luminescence color is dissolved; immersing said one edge portions of said first and second grooves in the first solution in the state where said third groove is apart from said first solution, and filling said second groove with said first solution while said stopper prevents said first solution from entering said first groove; removing said stopper; preparing a second solution in which an organic material of a second luminescence color is dissolved; immersing said one edge portion of said first groove in said second solution in the state where said second and third grooves are apart from said second solution, and filling said first groove with said second solution; preparing a third solution in which an organic material of a third luminescence color is dissolved; and immersing said other edge portion of said third groove in said third solution in the state where said first and second grooves are apart from said third solution, and filling said third groove said third solution.
 9. The method of manufacturing the organic EL device according to claim 8, wherein a plurality of said first, second and third grooves are formed for one pixel.
 10. The method of manufacturing the organic EL device according to claim 9, wherein at least one of said first, second and third grooves is formed in the different number from the number of the other grooves.
 11. The method of manufacturing the organic EL device according to claim 8, wherein at least one of said first, second and third grooves is formed in a different width from the other grooves.
 12. An organic EL device, comprising: a substrate; a first insulating film formed on said substrate; a first electrode formed on said insulating film; a second insulating film, which is formed on said insulating film and in which grooves are provided on a position corresponding to said first electrode; an organic EL layer that is formed in said grooves and whose one surface is electrically connected to said first electrode; and a second electrode electrically connected to the other surface of said organic EL layer.
 13. The organic EL device according to claim 12, wherein plural sets of said grooves are provided in one pixel region and the luminescence colors of the organic EL layers formed in each set of grooves are different from each other.
 14. The organic EL device according to claim 13, wherein the number of grooves of at least one set of each set is larger than the number of grooves of the other sets.
 15. The organic EL device according to claim 13, wherein the width of at least one set of each set is wider than the width of the grooves of the other sets.
 16. The organic EL device according to claim 12, wherein a buffer layer is provided at least between said first electrode and said organic EL layer or between said organic EL layer and said second electrode.
 17. A method of manufacturing an organic EL device, comprising the steps of: forming grooves in an insulating film on a substrate; filling said grooves with a solution in which a material that becomes a buffer layer between an organic EL layer and an electrode is dissolved; and drying said solution.
 18. A method of manufacturing an organic EL device, comprising the steps of: forming grooves in an insulating film on a substrate; filling said grooves with a solution in which a material that becomes an electrode is dissolved; and drying said solution. 